SIP Trunking FAQs

Keep hearing about SIP Trunking but unsure what all the fuss is about? This quick SIP trunking FAQ has everything you need to know...

Terry Lewis


Today, business communications are evolving at an incredible rate.

In the past, we used to rely exclusively on phones to connect with colleagues, customers, and contractors. Now, we can communicate via video, web conferencing, instant messaging and so much more. However, phones are still the heart and soul of many communication strategies.

The difference is, today’s companies can’t rely on voice connections alone to keep their communication stack ahead of the curve. Instead, they need a system that can handle any style of conversation, quickly, and cost effectively. As a result, the standard PSTN (Public Switched Telephone Network) is rapidly being replaced by IP known as SIP trunks.

With the potential to reach a value of £18 billion by 2024, the SIP trunking market is bigger, and more appealing than ever. The question is, how do SIP trunks actually work?

This quick SIP trunking FAQ will introduce you to the basics.

What is SIP?

Before you can understand SIP trunks, you need to know the basics of “SIP.”

SIP stands for Session Initiation Protocol, a technology used to establish a connection using a specific data network (usually the internet). Your VoIP telecom service uses a multitude of protocols to portray various communications over the web, and SIP is just one of those protocols.

SIP can carry a wide variety of different kinds of data, including emails, voice, videos, and more. SIP also has the potential to initiate multi-party communication through group conference calls and video discussions.

What is SIP Trunking?

SIP Trunking is the term that refers to the actual data connection that your SIP telephony provides. Unlike a traditional PTSN phone line, there are no physical wires required. Instead, a SIP trunk provider relies on your existing data circuit to manage your communication strategy.

Importantly, while SIP is the protocol most commonly used in VoIP systems, VoIP and SIP aren’t the same things. A typical VoIP service plan can include numerous protocols, including SIP trunking. VoIP telecommunications solutions also come with access to additional features and configuration options to help you create a full communication stack for your business.

How do SIP trunks work?

SIP trunks use something called a “mediation server,” to manage signaling and voice through a centralised resource (the enterprise IP network). SIP trunks essentially serve as a middleman between your phone system and an internet telephony service provider, or “ITSP.” A SIP trunk is your virtual connection between the ITSP and your organisation, managed either through a public IP network, or a virtual private network.

Because SIP trunking is specifically designed to act as the bridge between your on-site system and the cloud, it can deliver a high quality of sound. However, if you want to achieve crystal clear calls over SIP and VoIP, you’ll need a robust internet connection with plenty of bandwidth to support your call traffic.

Are there cost savings available with SIP trunking?

One of the main benefits of SIP trunks is that they generally provide a much lower TCO (total cost of ownership) than other telephony strategies. SIP trunking gives companies the opportunity to consolidate their communication providers and manage their entire “unified communication” network in the same environment. You also have the freedom to scale your bandwidth up and down according to your business needs.

Leading analytics company Gartner found that upgrading to SIP trunking from a typical legacy system can save a business as much as 50% in telephony fees.

Interested in finding out more? Contact Nice Network today to learn more about SIP trunking, VoIP, and the benefits of upgrading your communication strategy.